JPS5953612A - Dephosphorizing method by simultaneous blowing of gaseous oxygen and dephosphorizing agent under bath surface - Google Patents

Abstract

PURPOSE:To accelerate effectively dephosphorization reaction by blowing simultaneously a dephosphorizing agent under the bath surface of molten iron with an inert gas as a carrier gas while blowing O2 under the bath surface of the molten iron, respectively through an immersion lance. CONSTITUTION:Molten iron is desiliconized on the outside of a converter prior to converter refining and the slag formed at that time is removed. Gaseous oxygen 4 is blown through an immersion lance 3 under the bath surface of the molten iron 2 after the above-mentioned desiliconization in a molten iron ladle 1; at the same time, quicklime 6 as a dephosphorizing agent is blown under the bath surface of the molten iron 2 with N2 5 as a carrier gas. The lance 3 in this case is immersed under the bath surface of the molten iron, more preferably >=500mm. depth. O2 is blown preferably at 0.03-0.5Nm<3>/min flow rate per ton of the molten iron. The more effective dephosphorization reaction is performed by adding mill scale 7 further onto the bath surface in the above-described dephosphorization treatment.

Description

[Detailed description of the invention] The present invention relates to a method for dephosphorizing hot metal.

In recent years, attention has been paid to performing hot metal desiliconization and hot metal dephosphorization treatments in addition to hot metal desulfurization, which has conventionally been carried out as a pre-process in a converter refiner outside the converter furnace. The present inventors have already developed an effective method for treating hot metal outside the converter by injecting a dephosphorizing agent into the surface of the hot metal bath using an inert gas such as N 2 + Ar as a carrier gas through an immersion lance L7. However, the present invention is a more effective development of this method.

The gist of the present invention is to carry out the removal and sifting treatment of hot metal. At the same time from the left, blow in 1; That is '1°, and the gas f'
+i2 element and de-1i17 agent...” Time C? + Subsurface blowing dephosphorization method.

The details of this document will be described below.

fzu hot metal removed outside the furnace before entering the converter sheath] IIr + 111
B >II' of the slag produced at that time. ＼Do something.

Next, lower the lance 1 to 4 below the surface of the hot metal bath f'J5fl
(Immerse in the throat to a depth of 1.
釧; Infuse the bathing mask. At this time, 0.03 per ton of hot metal
Nm3/min 1d-Ton of hot metal at a flow h1 of 0.5 Nm3/min or less a) Collision f? l' l Nm' or more 12 Nm
It is desirable to inject an IA of 5 or less [2]. At the same time as gaseous oxygen is blown in, gaseous oxygen and t? Through another pipe of the same lance as the lance that blows gaseous oxygen near the flash point where the reactor reacts with C, an inert gas is injected into the tank at a voltage of 1 V.
CaO powder with a large particle diameter of 1 or less is blown into the molten steel; Fi becomes cheaper.

'12()2+Fe-+FeO(1) formula 2P -1-
5Fr+O-+ 5Fe +p2o5 (2) formula'! ), the blown cow rut gaseous oxygen is calculated using the above equations (1) and (2) and L120. , -1- The molten steel near the defect is partially heated to about 2oOo℃ by the reaction of C→Co (r+) formula.
1'-J, -, 1: Heat the C80 grains in the injected J and the dephosphorizing agent.
By soaking it in the bath for a little more than 1 hour, it becomes extremely active,
P2O5 produced in the reaction of formula (2) above is effectively fixed by the reaction of formula (4) of P2O5+4CRO-+P2O5.4CaO. At this time, tll, ore,
When iron oxide such as mill steel is immersed into the hot metal bath surface, the reaction of the above formula (2) occurs at the hot metal bath surface as well.
(t, molten sword: The reaction of the above formula (4) at the bath surface efficiently proceeds as jHtr, making it possible to effectively dephosphorize.

In addition, as a dephosphorizing agent, CaO powder and Jl were injected with iron powder such as Mill Scale at the time of fitting.
, l-, +, Since a 1u combined oxide of CnO and FeQ is generated, the liquefaction temperature of the dephosphorizing agent is lower than that of CaO, and the liquefaction temperature of the dephosphorizing agent is lower than that of the hot metal. It liquefies and becomes 7 easy to liquefy. Therefore, a highly oxidizing and highly oxidizing slag is generated in the molten steel bath, and the reactions of formulas (1) and (4) occur promptly and efficiently, thereby achieving effective dephosphorization.

[2, 7, special, +ll; To 11, the addition of iron oxide causes an increase of 1 ml of de-blowing, and an increase in the length of blowing time or an increase in swiping of hot metal.
This can easily lead to increased losses. Still, the lance structure has two pipes for gaseous oxygen and dephosphorizing agent, and the r1 Yuka iron (+') is used as a machining. This is because it is necessary to separate the gas pipeline from the dephosphorizing pipeline due to the problem of water leakage, and it is easier to install and maintain than using two lances. It's better than that.

Below, we will use the diagrams to energize and clarify the words 本屏 and 明.

2B1 Diagram ti Explanation of the present invention, clear diagram, 1 welding mill: Kabura j12
Hot metal, 3 V dips, 4 piles 1: 1 gas, 5 it
N7 gas, 6 stone powder, 7 mill scale.

As shown in the figure, gaseous oxygen 4 is blown into the surface of the hot metal bath through a lance, and at the same time B125 is transported and
Then, quicklime 6 is similarly blown below the surface of the hot metal bath.

Also, place the mill scale 7 on the bath surface 1. Therefore, the dephosphorization reaction can be carried out effectively.

l;7. Below is the real MQ f'11 t, '+7f, -h, 4. .

7ζ1・? i Fl, l! 'i 131njl iL, n :1 tonno blast furnace j'2i needle (r: Cl' :j: horn in the pot) 1. At the same time as gaseous oxygen is blown into the hot metal bath 1.τtn And then e1'? Converting eJri ・1) He was a person and - C, but he attacked Le. Next, 1 silicon 4 liters 1 η1 = /1.71+! 4
t、、Dasurugui C 1・1:・1；□) in the evening jj,
j7. Y, 11 is A” 1: ln%, or 0.5
k4717j f,ru:+1. 'l'j-i'4:
l-, -ta.

Next, use 6. Scout Lance and 7. Mel'G'11. '6'i
Ili i' While blowing 15j body acid iΔ on the n゛ of I +n, the same +1'+1 - this best friend 1 (° 1 diameter less than 1 square) all ri1 of raw stone powder 5 bodies rc 1′ different from
N2 gas, which is an inert gas, is passed through the f path Ifj', +
Melting as a bath: Blow into the bath surface to a depth of 1 m, and at the same time melt the mill scale and immerse it in the valley surface.1.
304) I am going to press the book office. 4' The actual report
i f8'II Is the connection li of 1 and 2 fj?

? 2'S RI-41 Old ('L tf y
, ゛te'A',-2,N2:/i' Sui I: i! ! m) f-” no l, 1
: fp (Tuesday II diameter) n-PJ, [' ) raw i)
'ζ Oni) (7+, ', l, 6 inscription, -,: I
゛ 111F 11-'1, Niho Ho -Louis 1 Yo S ”, Bi -Mitto Scale Bathing surface” , shaft side 1 , j'r
, the results of 1 and 2 are i't 7'7-0 or more real/u'+
11+'l :lS , ,1:hi11',11佼1su11に1υ1/,c)1'k Ill, ,Ill
i yarn',) Bath 1: q, [PJr<Fit 2 Figure I
FM;+4゛a. Comparison (J1 example with 11., Berumi noi ii ((:l) after removal of 11i treatment with phosphorus iris j: 1
i is for lp lime's Ill) regardless of 11'n's
Mr. 1 (X'l W'77! Fixed 1. Tier).

Kobi'? :'i,! P1: Book, 'l'i in January
l'('+:'1., 7) Spy lance 1. and gas ('+I9 v?i+ ;iii: Blow below the bath surface 1
Δ9- From the sea, simultaneously pump inert gas 1f and 12, then remove J with 1 and 3 pieces of lime powder to 1, and inject Ji agent θ゛ Already 6 :1. De-, (,'i
III that l'I method l/s i1 is effectively Ji method!
IQ+4]1).

4.1 The detailed explanation of the invention, Figure I () 1, 1 explanatory diagram of the method of the present invention, Figure 2 Figure 1 + No. 1 of the invention! It is an explanatory diagram of I'-.

1: ・15, 1 whirlpool, 2: (ken 6 ahead, 3: (, ramoe lance, 4: '1 camp I"J2, "j□, 5: N2 gas, 6; quicklime powder, 7 : Mill 4 kale, shi); Firefly'>, q: Mill scale.

Figure 7

Claims (1)

[Claims] When performing the dephosphorization treatment of I@, gaseous oxygen is blown under the surface of the hot metal bath through an immersion lance, and at the same time, a dephosphorization agent mainly consisting of quicklime powder is blown under the surface of the hot metal bath using an inert gas as a carrier gas. Is it possible to inject I+'-'? This is a 1'1 method of dephosphorization by simultaneously blowing gaseous oxygen and dephosphorizing agent under the bath surface.